Figure 54: LSP Creation, Downstream-Unsolicited, Independent Control
Related Topics â– MPLS Label Switching and Packet Forwarding on page 209
â– MPLS Label Distribution Methodology on page 218
â– MPLS Label Distribution Protocols on page 229
â– Topology-Driven LSPs on page 246
Mapping IP Data Packets onto MPLS LSPs
IP packets are mapped onto LSPs by one of the following methods:
â– RSVP-TE tunnels can be referenced directly by static routes that you configure.
You can determine which routes (routes destined for which subnets) to direct
through the LSP and issue the appropriate ip route commands, as shown in the
following example:
host1(config-if)#ip route 10.15.21.16 tunnel mpls:1
You cannot create any static routes until the tunnel interface has been created.
However, the tunnel does not have to be active before you create the static
routes.
â– RSVP-TE tunnels are announced to IS-IS and OSPF; the IGP then uses the tunnels
as next hop interfaces for its SPF calculations. For this method, you must issue
the tunnel mpls autoroute announce command. When the LSP is established,
the ingress LSR announces the LSP endpoint to the IGP. This is also referred to
as registering the LSP. The IGP then recalculates the shortest path for all routes
destined for or beyond that endpoint. You can choose to register endpoints with
both IS-IS and OSPF. The following is an example registration command:
host1(config-if)#tunnel mpls autoroute announce isis
â– For topology-driven LSPs, LDP can modify the IP routing table to use MPLS next
hops in the routing table, replacing the regular IP next hops for the corresponding
routes.
â– For labeled BGP routes, BGP adds routes with MPLS next hops to the appropriate
VR or VRF routing table.
220 â– Mapping IP Data Packets onto MPLS LSPs
JUNOSe 11.1.x BGP and MPLS Configuration Guide
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